Data communications within vehicles has developed extensively over the years. The truck industry, for example, has for many years used tractor/trailer combinations to transport cargo over the roadways to intended destinations. As shown in FIG. 1, an ensemble of components, including a tractor 10 and a trailer 20 mechanically couple together so that the tractor can pull the trailer, from a vehicle 5, often referred to as a “rig,” which can transport cargo in an efficient and cost effective manner. Various links between the tractor and the trailer provide vehicle subsystems with power and/or control signals to operate. Hydraulic, pneumatic, electrical, and other subsystems on the rig have associated electrical conductors and pneumatic lines running therebetween so these subsystems can operate. These electrical conductors and pneumatic lines typically include quick-disconnecting, standardized connectors and couplers so that rig components, such as tractors, trailers and dollies (the short trailers used to couple multiple trailer strings), may be easily interchanged.
Because connectors in rigs are standardized, a single tractor may be connected to and used to transport any number of different trailers throughout its operational life. Because of this interchangeability, components are frequently traded, loaned, and leased among users. For example, a trailer may be hauled to a first terminal or other delivery location where it is detached from the tractor which delivered it and connected to another tractor—the new rig destined for another terminal. Thus, a single trailer may be under the control of several different concerns, including trucking companies, railroads, overseas shippers, and truck brokers, and may be used by several different tractor/trailer operators. The same is true for other components, such as tractors, dollies, and shipping containers as well as many other types of vehicles.
Because of the interchangeability and mobility of these components, trucking companies, freight brokers, law enforcement officials, and others involved in the transport industry have developed methods to track rigs and their components. While trucking companies and other shippers desire to keep track of cargo and rolling stock, law enforcement and other regulatory agencies desire to monitor truck licensing, ownership, cargo content, and driver workloads. Techniques have been developed for tracking rigs and their components as the rigs travel between cargo terminals, delivery points, weigh stations, and the like, but these techniques generally are cumbersome and limited in effectiveness and information capacity. Many tractors, trailers, and other components are identified using simple numbering systems, i.e., a serial or other number is painted on or otherwise applied to a surface of the component. These numbers typically are read and recorded by human operators—a time-consuming process which represents an undesirable inefficiency in an industry in which time is usually critical. Besides being inefficient, the human link in the accounting process increases the chances for error and omission, particularly under conditions of darkness or obscured visibility.
In addition, a serial or other identification number may fail to convey a complete identity. Cargo contained within a trailer generally is not identifiable by the trailer's identification number absent a predetermined cross-reference between the number and the cargo. Although such a cross-reference typically can be supplied through a freight management database, elaborate communications systems and recording procedures may be required to ensure data integrity. Failures in the link of the accounting chain may result in erroneous component and cargo designations leading to confused shipments and misplaced components.
Bar-code or magnetic-stripe identification systems reduce the human error involved in the use of numbering systems, but have drawbacks of their own. Because of the need to make codes or magnetic stripes accessible to readers, codes and stripes are typically affixed to surfaces of the rig which are exposed to wind, rain, salt, and other environmental contaminants which may render the codes or stripes unreadable. In addition, reading a bar code or magnetic stripe typically requires close proximity between the reader and the code or stripe, generally precluding remote reading or reading while the rig is in motion. Moreover, bar codes and magnetic stripes have a relatively limited informational capacity.
Accordingly, there is a need for improved systems and methods for identifying rigs and their components which have a high information transfer capacity and which can dependably and accurately operate in the demanding environments in which the rigs typically operate. Moreover, these methods should be inexpensive and easily retrofitted onto existing equipment without major compatibility problems.
Additionally, various links between the tractor and the trailer provide vehicle subsystems, e.g., hydraulic, pneumatic, or electrical, with power and/or control signals to operate effectively. These subsystems have associated electrical conductors, pneumatic lines, or hydraulic lines extending between the tractor and trailer(s) so that these subsystems can effectively operate.
Data communications between a tractor and trailer for these subsystems also has been developed. An example of this data communications can be seen in U.S. Pat. No. 5,488,352 by Jasper titled “Communications And Control System For Tractor/Trailer And Associated Method” which is assigned to the common assignee of the present application. As described in this patent, the use of the Society of Automotive Engineering (“SAE”) standard J1708 titled “Serial Data Communications Between Microcomputer Systems In Heavy Duty Vehicle Applications” and SAE standard J1939 are also known for data communications in the heavy duty vehicle environment.
Only recently, however, has the heavy duty vehicle industries begun to use sophisticated electrical electronic subsystems in and associated with these vehicles to perform varied tasks that usually involve data manipulation and transmission. Previously, computers, controllers, and computer-type electrical systems were simply not found in these vehicles, such as the tractor and trailer combinations or recreational vehicles, in a significant manner. Much of this previous slow, or lack of, development and advances could be attributed, for example, to the lack of governmental or other authoritative initiatives which would have otherwise required systems to be installed on these heavy duty vehicles to include sophisticated electronics and data communications.
Although only recently have advances been made with data communications in the heavy duty vehicle industries, many of the advances require extensive retrofitting or extensive additions to the heavy duty vehicle. Accordingly, many vehicle owners have been hesitant to adopt and purchase sophisticated electronics and data communications because of the expense and uncertainty with the advances in the technology. Yet, having the capability to monitor and communicate with the various electronic subsystems of a heavy duty vehicle such as a tractor-trailer truck or recreational vehicle can be beneficial to the driver, the owner, governmental officials or agencies, and others having an interest in the heavy duty vehicle industries.
Still further, many of today's vehicles are equipped with sophisticated computer systems. These computer systems typically include a central computer that receives data from sensors located throughout the vehicle. The sensors record data information concerning systems of the vehicle, and the central computer system uses this information to control the operation of the vehicle, store the data for historical purposes, and/or analyze the data for diagnostic purposes. For example, many vehicles include central computer systems that receive data from sensors such as throttle sensors, oxygen sensors, and fuel flow sensors to regulate the engine.
In addition to providing data for operation of the vehicle, many vehicle computer systems include sensors that provide data concerning the various systems of the vehicle for use in diagnostic and maintenance. For example, many heavy duty vehicles now include sensors that provide data relating to safety systems, such as the status of the brakes of the vehicle. Additionally, many systems provide logistics data relating to the vehicle, such as mileage, fuel tank levels, fuel mileage, status of contents hauled in the vehicle, etc.
To access data from the computer system, many of today's vehicles include electrical pin-out connectors that are accessible for connection. In these systems, a diagnostic device may be connected to the pin-out connector to receive and transmit data to and from the onboard computer of the vehicle. In light of this, several interrogation devices have been created in the past few years that interface with the pin-out connector of a vehicle and transmit and receive data relating to the operation of the vehicle and status of its various systems. Although these conventional systems are effective for receiving data from and transmitting data to the data bus of the vehicle, these interrogation devices require physical connection to the vehicle, which may not be desirable in situations where the vehicle is either in transit or is remote from the interrogation device requesting data input.
Although remote, wireless communication with the computer system of a vehicle is typically desired, the physical limitations of the communication infrastructure of most vehicles hinder the move to wireless communication. For instance, the communication systems of many conventional vehicles, such as heavy duty vehicles (e.g., tractor-trailer vehicles) use communication protocol that requires real-time communication with the vehicle.
Specifically, many heavy duty vehicles include a data bus that is operated using one of two bus standards, either SAE J1708 or J1939. Communication on the data bus of these vehicles may be problematic due to the nature of the J1708 and J1939 standards. For example, a data bus that uses the J1708 standard is a differentially driven, twisted pair. The data bus of this system is half duplexed such that data transmitted on the data bus is transmitted on both of the twisted pair of wires, where the data transmitted on one of the twisted pair of wires is mirrored with respect to the other twisted pair wire. Because data transmitted on the bus is transmitted on both wires of the bus, the data bus does not have a transmit and receive line. Further, systems wishing to transmit data on the data bus must monitor the data bus for an idle state where data is not being transmitted, before the system transmits data on the data bus.
As discussed, many conventional interrogation or other types of data communication devices have been designed for use in direct electrical communication with the data bus of a vehicle. These systems, to some extent, do not experience problems with the infrastructure or protocol of the data bus because they are in direct electrical connection with the data bus. This direct electrical connection allows these systems to monitor the idle states of the data bus in real-time. For this reason, in the past few years several interrogation devices have been developed for transmitting and receiving data from the data bus of a vehicle using direct electrical communication with the data bus. Importantly, these interrogation devices typically use software programs that are specifically designed to interface with the data bus in real-time. The software programs monitor the bus for idle states and transmit data to the bus. These systems, however, still have extensive limitations.